1. Field of the Invention
This invention relates to a stimulable phosphor panel. This invention particularly relates to a stimulable phosphor panel, which is to be located in a radiation image read-out apparatus and from which a radiation image is to be read out.
2. Description of the Related Art
Radiation image recording and reproducing systems comprising radiation image recording apparatuses, radiation image read-out apparatuses, and the like, in which stimulable phosphors are utilized, have heretofore been known as computed radiography (CR) systems. With the CR systems, a radiation image of an object, such as a human body, is recorded as a latent image on a sheet provided with a layer of the stimulable phosphor (hereinafter referred to as a stimulable phosphor sheet). The stimulable phosphor sheet, on which the radiation image has been stored, is then exposed to stimulating rays, such as a laser beam, which cause the stimulable phosphor sheet to emit light in proportion to the amount of energy stored on the stimulable phosphor sheet during exposure of the stimulable phosphor sheet to the radiation. The light emitted by the stimulable phosphor sheet, upon stimulation thereof, is photoelectrically detected and converted into an electric image signal. In this manner, the image signal representing the radiation image of the object is acquired.
As a recording medium to be used in the radiation image recording and reproducing systems described above, a stimulable phosphor panel, which comprises a support plate and a stimulable phosphor layer overlaid on the support plate, has heretofore been known. After the stimulable phosphor panel, on which a radiation image has been stored, has been subjected to a radiation image read-out operation for reading out the radiation image from the stimulable phosphor panel, erasing light may be irradiated to the stimulable phosphor panel in order to release energy remaining on the stimulable phosphor layer of the stimulable phosphor panel. The thus erased stimulable phosphor panel is capable of being used again for the recording of a radiation image. The stimulable phosphor panel is thus capable of being used repeatedly for the recording and the readout of a radiation image.
As an apparatus for performing the radiation image recording operation and the radiation image read-out operation, a radiation image recording and read-out apparatus, which comprises both the radiation image recording apparatus and the radiation image read-out apparatus, has heretofore been known. In the radiation image recording and read-out apparatus, the stimulable phosphor panel is secured to an apparatus main body, and the radiation image recording operation and the radiation image read-out operation are performed iterately on the stimulable phosphor panel. After the stimulable phosphor panel located in the radiation image recording and read-out apparatus has been used for a long period, the radiation image recording performance and the light emission performance of the stimulable phosphor panel become bad. Therefore, the stimulable phosphor panel is periodically changed over to a new stimulable phosphor panel.
In cases where the stimulable phosphor panel located in the radiation image recording and read-out apparatus is changed over to a new stimulable phosphor panel, the change-over operation is performed at a site at which the radiation image recording and read-out apparatus is operating. Therefore, it is desired that the change-over operation is capable of being performed quickly.
However, it is necessary that a new stimulable phosphor panel be located accurately at a predetermined position within the radiation image recording and read-out apparatus. (For example, it is necessary that a surface of the stimulable phosphor layer of the stimulable phosphor panel be located with an accuracy within the range of ±25 μm with respect to a predetermined reference position.) However, for reasons of producing processes, dimensions of the stimulable phosphor panel vary for different stimulable phosphor panels. Therefore, the position adjustment described above is performed with respect to each of different stimulable phosphor panels. Accordingly, the problems occur in that a long time is required to perform the position adjustment.
The problems described above are encountered commonly to radiation image read-out apparatuses, in which the stimulable phosphor panel is located, and a radiation image is read out from the stimulable phosphor panel.